Pneumatic spring for railroad cars

ABSTRACT

A pneumatic spring for use between the lateral frame members of the frame and bogie in a railroad car or a streetcar has a torusshaped diaphragm having two coplanar ring-shaped beads the outer of which is sealingly secured to the frame and the inner of which is sealingly secured to a cap which is coupled to the bogie, preferably by way of a rubber spring. The coupling between the cap and the frame member of the bogie may comprise an antifriction bearing or a friction bearing to reduce the stressing and wear on the diaphragm. The interior of the diaphragm communicates with a plenum chamber in the frame member of the frame and the cap is provided with a projection which abuts against a partition in the frame forming the compartments of the plenum chambers in the event of a failure of the pneumatic spring.

United States Paten [1 1 Brand et a1.

[451 Jul 30, 1974 PNEUMATIC SPRING FOR RAILROAD CARS [73] Assignee:Waggonfabrik Verdingen AG,

Dusseldorf, Germany 22 Filed: Dec. 10, 1971 21 App]. No.: 206,632

[30] Foreign Application Priority Data Dec. 11, 1970 Germany 2060960[52] US. Cl. 267/3, 105/197 B, 105/199 R,

[51] Int. Cl. B6lf 5/10, B6lf 5/50, F16f 9/04 [58] Field of Search...105/141, 150, 197 A, 197 B, 105/199 R, 199 S, 453; 267/3, 65 A, 122, 35

3,092,039 6/1963 Lich 105/150 3,319,952 5/1967 Travers 267/35 X3,601,063 8/1971 Dean 267/3 X FOREIGN PATENTS OR APPLICATIONS 1,207,42012/1965 Germany 105/199 R 7,018,231 9/1970 Germany 105/197 B PrimaryExaminerLloyd L. King Assistant Examiner-Howard Beltran Attorney, Agent,or FirmMichael S. Striker 7] 9 ABSTRACT A pneumatic spring for usebetween the lateral frame members of the frame and bogie in a railroadcar or a streetcar has a torus-shaped diaphragm having two coplanarring-shaped beads theouter of which is sealingly secured to the frameand the inner of which is sealingly secured to a cap which is coupled tothe b0- gie, preferably by way of a rubber spring. The coupling betweenthe cap and the frame member of the bogie may comprise an antifrictionbearing or a friction bearing to reduce the stressing and wear on thediaphragm. The interior of the diaphragm communicates with a plenumchamber in the frame member of the frame and the cap is provided with aprojection which abuts against a partition in the frame forming thecompartments of the plenum chambers in the event of a failure of thepneumatic spring.

9 Claims, 5 Drawing Figures PAH-INTER JUL 3 0 2914 SHEEI 2 5F 5 PATENTEDJUL 3 01914 SHEET 3 OF 5 PATENIED JUL 3 0 I974 SNEEI 5 BF 5 PNEUMATICSPRING FOR RAILROAD CARS BACKGROUND OF THE INVENTION The presentinvention relates to improvements in pneumatic springs for use inrailroad cars, streetcars or the like rail-mounted vehicles. Moreparticularly, the invention relates to improvements in pneumatic springswhich can be used between the wheel-mounted beamfree or cradle-freetruck or bogie and the body and frame of a railroad car, streetcar,tramway or the like.

German printed publication No. 1,207,420 discloses a railroad car withtwo pneumatic springs interposed between the lateral frame members ofthe cradle-free bogie and the lateral frame members of the frame or bodyof the vehicle. Each spring comprises a torusshaped diaphragm whichresembles a ring-shaped trough having an open side facing the undersideof the frame and bounded by two beads including an outer bead which issecured to the frame and an inner bead which is coupled to the truck.The two beads are normally located in two different horizontal planes,namely, the inner head is disposed at a level below the outer bead. Itwas found that, when the vehicle travels in a sharp curve, the stressingof and the restoring forces acting upon the diaphragm are verypronounced. The resulting wear on the wheels can reach such proportionsthat it adversely affects the running of the vehicle along the rails.The substantial restoring is attributable to relatively high rigidity ofthe diaphragm, and such rigidity can also cause a slippage of and theresulting wear upon the beads especially that bead which is located atthe lower level and is secured to a bearing ring on a pipe of the bogiein a manner not unlike the connection between an automobile wheel and atubeless tire.

German Utility Model No. 7,018,231 discloses a modified pneumatic springemploying a diaphragm similar to that of the German printed publicationNo. 1,207,420 wherein the lower or inner bead of the diaphragm issecured to a rim provided on a tube which is mounted on the bogie. Ananti-friction bearing is installed between the rim and the upper end ofthe tube. The rim has a cupped extension which is received in the tubeand accommodates the component parts of an auxiliary or emergency stopwhich becomes operative in the event of failure of the pneumatic spring.The just described construction comprises a very large number of partswhich contribute to the high initial cost of the pneumatic spring.

SUMMARY OF THE INVENTION and improved mounting for the torus-shapeddiaphragm of a pneumatic spring between the bogie and the frame of arail-mounted vehicle.

An additional object of the invention is to provide novel and improvedconnections between the beads of the diaphragm and the frame and bogieof a streetcar or the like.

The invention is embodied in a vehicle, such as a railroad car or astreetcar, which comprises a wheelmounted bogie or truck, a vehicleframe located above the bogie, and cushioning means including at leastone pneumatic spring which is interposed between the frame and the bogieand comprises a torus-shaped hollow flexible diaphragm having an innerring-shaped bead and an outer ring-shaped bead spacedly surround ing theinner bead and being normally at least substantially coplanar with theinner bead, connecting means sealingly securing the outer head to theframe, a cap surrounded by and sealingly secured to the inner bead andhaving an arresting portion normally spaced from and located at thelevel below the adjacent portion of the frame, and coupling meanssecuring the cap to the bogie. The frame has a plenum chamber incommunication with the interior of the diaphragm, and the diaphragm hasan open upper side extending between the two beads and facing the frame.

The novel features which are considered as characteristic of theinvention are set forth in particular in the appended claims. Theimproved pneumatic spring itself however, both as to its constructionand its mode of operation, together with additional features andadvantages thereof, will be best understood upon perusal of thefollowing detailed description of certain specific embodiments withreference to the accompanying drawing.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a fragmentary verticalsectional view of a rail-mounted vehicle embodying a pneumatic springwhich is constructed in accordance with a first embodiment of theinvention and is shown in central vertical section;

FIG. 2 is a similar view of a portion of a vehicle embodying a modifiedpneumatic spring;

FIG. 3 is a similar view of a vehicle embodying a third pneumaticspring; and

FIG. 4 is a similar view of a vehicle embodying a fourth pneumaticspring and FIG. 5 is a fragmentary side view of a railway vehicle havinga wheel mounted track, a frame, and a pneumatic spring interposedbetween track and frame.

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 5 partly illustrates arailway vehicle RV having wheel mounted trucks or bogies B, only one ofwhich is shown, and a pneumatic spring 1, 8, which will be describedlater on in detail, between the truck B and the frame F of the vehicle.

Referring now to FIG. 1, there is shown a pneumatic spring which can beinstalled between a lateral frame member 4 of the body or frame Fforming part of a railroad car or streetcar RV and a lateral framemember 11 of the bogie or truck B which is mounted on wheels, runningalong a pair of rails. The locations in which two pneumatic springs ofthe type shown in FIG. 1 can be mounted between the bogie B and thevehicle frame F are shown in FIGS. 1 and 2 of the aforediscussed Germanprinted publication No. 1,207,420.

The pneumatic spring of FIG. 1 comprises a torusshaped hollow flexiblediaphragm 1 having an outer ring-shaped head 2 and an inner ring-shapedbead 3 which latter issurrounded by and is normally coplanar withtheouter bead 2. The connecting device which sealingly secures the outerbead 2 to the frame member 4 comprises a clamping ring 5 and screws,bolts or analogous fasteners 5a. The inner bead 3 surrounds and issealingly secured to a cap 6 which has a downwardly extendingcylindrical portion 7 adjacent to the external surface of the diaphragm1 immediately below the bead 3. The connection between the bead 3 andcap 6 is of the type similar to that between a tubeless tire and a rimon the wheel of an automotive vehicle. The cylindrical portion 7 of .thecap 6 serves as means for properly centering the diaphragm 1 and forpreventing inward bulging of the diaphragm in the region below the bead3. The upper side of the cap 6 is provided with a rib, rail or analogousarresting portion or projection 12 which serves'as an auxiliary oremergency stop in the event of failure of the pneumatic spring and thenabuts against an internal portion or portions 13 of the frame 4. .Thus,if the diaphragm 1 is destroyed or punctured, the projection l2 abutsagainst the underside of the portion 13 and thereby prevents furtherdescent of the respective side of the frame F toward the bogie B.

The partitions 13 is provided with one'or more openings or ports 13a forthe flow of a pressurized gaseous fluid which fills the interior of thediaphragm l and a plenum chamber 15 of the frame F. Since the upper sideof the diaphragm 1 between the beads 2 and 3 is open, the interior ofthe diaphragm is free'to communicate with all compartments of the plenumchamber 15, namely, with; the compartments above and below the partition13. 1

The'coupling meansbetween the frame member 11 of thebogieB and the cap 6comprises a laminated elastomeric spring 8 consisting at leastessentially of natural or'synthetic rubber, a lower flange 8A whichconnects the lower end of the spring 8 to the frame member 11 by meansof threaded fasteners 88, and an upper flange 8D which connects theupper end of the spring 8 tothe-cap 6 by means of threaded fasteners815. Thus, the respective ends of the rubber spring 8 are rigidly.connected with the cap 6 and with the frame member 1 1. X

ln'theembodiment of FIG. 2,:the cap 9 constitutes theupper race of anantifriction bearing 25 which forms part of thecoupling means betweenthe inner bead 3 of the diaphragm 1 and the frame member 11. The lowerrace of the bearing 25 is secured to the flange 8D by the fasteners 8E.Rolling elements 9a are interposed between the races 9 and 10.Otherwise, the pneumatic spring of FIG. 2 is identical with thepneumaticspring of FIG. 1, i.e., the heads 2, 3 are normally located in a commonhorizontal plane and the two compartmentsof the plenumchamberlS-are-free to communicate witheach other and with the interiorof the diaphragm l.

. In the embodiment of FIG. 3, the coupling means between the cap 6 andthe frame member 11 of the bogie B comprises an antifriction bearing 26having an upper race 27'which is rigid with the flange 8A, a lower race14 which is bolted to theframe member 11, and rolling elements 28interposed between the races 14, 27. Otherwise, the pneumatic spring ofFIG. 3 is identical with. the pneumatic spring of FIG. 1.

In the embodiment of FIG. 4, the cap 16 constitutes the/outer sleeve ofa friction bearing 29 which forms part of the coupling means between thebead 3 and the frame member 11. The inner sleeve 17 of the frictionbearing 29 is bolted to the flange 8D.

The purpose of the rubber springs 8 is to take up mainly verticalstresses. The manner in which the frame F is turnably connected with thebogie B is not shown in the drawing; such connection may comprise anantifriction ball bearing mounted on the frame F and having a lower racecooperating with arms'or leversprovided on the bogie B. Reference may behad to FIG. 2 of the aforementioned German printed publication No.1,207,420.

An important advantage of the constructions shown in FIGS. 2-4 is thatthe bearings in the coupling means between the inner bead 3 and theframe member 11 of the bogie B reduce the likelihood of subjectingthediaphragm l to excessive torsional stresses. This .prolongs the usefullife of the diaphragm. The rubber spring 8 reduces the likelihood ofexcessive stressing of the diphragm 1 when the vehicle travels along asharp curve and the distance between the lateral frame members 4 and 11changes. Another advantage of the improved pneumatic spring is that itcomprises a relatively small number of simple parts which can be readilyassembled or taken apart. Since the diaphragm l is subjected torelatively small torsional stresses as a result of which its normalcondition can be reestablished by resorting to relatively smallrestoring forces, the useful life of the diaphragm considerably exceedsthe useful life of diaphragms in conventional pneumatic springs. Also,the wear on the wheels of the bogie B is less pronounced and the runningof wheels on the rails ismore satisfactory than in rail-mountedconveyances employing conventional pneumatic springs. a

Without further analysis, the foregoing will so fully reveal the gist ofthe present invention that others can, by applying current knowledge,readily adapt it for various applications without omitting featureswhich fairly constitute essential. characteristics of the generic andspecific aspects of our contribution to the art and, therefore, suchadaptations should and are intended to be comprehended within themeaning and range of equivalence of the claims. What is claimed as newand desired to be protected by Letters Patent is'set forth intheappended claims: l. A pneumatic spring arrangement comprising, incombination, plenum chamber means having an opening; pneumatic springmeans including a torus-shaped hollow flexible diaphragm having an innerring shaped bead and an outer ring shaped bead spacedly surrounding saidinner ring shaped bead; connecting means sealingly securing said outerring shaped head to said plenum chamber means around said openingthereof; a cap surrounded by and sealinglysecured to said inner ringshaped .bead, said cap having a rigid projecting portion projectingtoward a portion of said plenum chamber means located above saidprojecting portion,

. and coupling means adapted to secure said cap to a maintain said outerbead at least substantially coplanar with said inner bead and saidprojecting portion of said cap spaced from said portion of said plenumchamber means, said projecting portion however moving during springingaction through said opening at least partly into said plenum chambermeans.

2. A combination as defined in claim 1, wherein said coupling meansincludes an antifriction bearing having an upper race constituting saidcap, a lower race and rolling elements disposed between said races.

3. A combination as defined in claim 1, wherein said coupling meanscomprises a friction bearing having two coaxial sleeve-like portions oneof which constitutes said cap and the other of which is rotatablerelative to said one sleeve-like portion.

4. A combination as defined in claim 1, wherein said coupling meanscomprises a laminated rubber spring.

ing a path for the flow of a pressurized fluid between saidcompartments.

7. A combination as defined in claim 1, wherein the common plane of saidbeads is normally a substantially horizontal plane.

8. A combination as defined in claim 1, wherein said cap comprises acylindrical portion whose axis is substantially normal to the commonplane of said beads and said diaphragm further comprises a substantiallycylindrical portion immediately adjacent to said inner bead andsurrounding said cylindrical portion of said cap in engagementtherewith.

9. A combination as defined in claim 1, wherein said plenum chambercomprises a rigid partition extending transversely therethrough andsubstantially parallel to said inner bead, said partition dividing saidchamber into two compartments, at least one port in said partitionproviding communication between said compartments, a portion of saidpartition forming said portion of said frame.

1. A pneumatic spring arrangement comprising, in combination, plenumchamber means having an opening; pneumatic spring means including atorus-shaped hollow flexible diaphragm having an inner ring shaped beadand an outer ring shaped bead spacedly surrounding said inner ringshaped bead; connecting means sealingly securing said outer ring shapedbead to said plenum chamber means around said opening thereof; a capsurrounded by and sealingly secured to said inner ring shaped bead, saidcap having a rigid projecting portion projecting toward a portion ofsaid plenum chamber means located above said projecting portion, andcoupling means adapted to secure said cap to a cushioned member, saidplenum chamber means communicating through said opening with theinterior of said torus-shaped hollow flexible diaphragm in which the airis pressurized in such a manner as to normally maintain said outer beadat least substantially coplanar with said inner bead and said projectingportion of said cap spaced from said portion of said plenum chambermeans, said projecting portion however moving during springing actionthrough said opening at least partly into said plenum chamber means. 2.A combination as defined in claim 1, wherein said coupling meansincludes an antifriction bearing having an upper race constituting saidcap, a lower race and rolling elements disposed between said races.
 3. Acombination as defined in claim 1, wherein said coupling means comprisesa friction bearing having two coaxial sleeve-like portions one of whichconstitutes said cap and the other of which is rotatable relative tosaid one sleeve-like portion.
 4. A combination as defined in claim 1,wherein said coupling means comprises a laminated rubber spring.
 5. Acombination as defined in claim 4, wherein said coupling means furthercomprises an antifriction bearing having a first race secured to saidrubber spring, a second race, and rolling elements interposed betweensaid races.
 6. A combination as defined in claim 1, wherein said plenumchamber comprises several compartments and said frame is provided withat least one Port establishing a path for the flow of a pressurizedfluid between said compartments.
 7. A combination as defined in claim 1,wherein the common plane of said beads is normally a substantiallyhorizontal plane.
 8. A combination as defined in claim 1, wherein saidcap comprises a cylindrical portion whose axis is substantially normalto the common plane of said beads and said diaphragm further comprises asubstantially cylindrical portion immediately adjacent to said innerbead and surrounding said cylindrical portion of said cap in engagementtherewith.
 9. A combination as defined in claim 1, wherein said plenumchamber comprises a rigid partition extending transversely therethroughand substantially parallel to said inner bead, said partition dividingsaid chamber into two compartments, at least one port in said partitionproviding communication between said compartments, a portion of saidpartition forming said portion of said frame.